電阻式記憶體之可靠度量測系統之組立

Abstract

電阻式記憶體（Resistive Random Access Memory，RRAM）為極有潛力的次世代記憶體之一，而記憶體元件的可靠度是評斷其實用性的重要依據。本研究以電腦為主機，利用Keithley 2400電源電錶搭配Agilent 81110a脈衝產生器，自行撰寫LabVIEW程式語言以擷取電性數據，主要特色為捨棄一般量測系統中常見的Switching Box，以時間軸的概念設計系統之做動，建立一套可行的記憶體元件可靠度量測系統。 此研究共建立三套量測系統，分別為：（1）自動掃讀I-V曲線系統，其控制Keithley 2400自動重複四段單獨的掃描電壓，以LabVIEW程式做即時監控並擷取所有I-V-R原始資料，且能自動判別RHRS、RLRS、VSET、VRESET，以利後續的試片分析與探討；（2）半自動Endurance量測系統，搭配Keithley 2400以及Agilent 81110a，以時間精準控制Agilent 81110a的脈衝輸出數量及參數，再以手動換針的方式切換至Keithley 2400掃描電壓，以得到週期對應電阻值之圖形以及各週期之I-V曲線；（3）自動長時間Retention量測系統，以Agilent 81110a脈衝輸出做為記憶體轉換電阻的時間起點，並控制Keithley 2400量測電阻值的時間間隔。 整套系統具有跨廠牌、自由度高、資料擷取方便度、成本低等優點，但因為捨棄’了Switch Box，使得Endurance量測系統必須以手動換針，無法達到全自動化量測之目的。

Resistive random access memory (RRAM) has been recognized as the next-generation nonvolatile memory and its reliability is one of the key issues to access the device performance. In this study, personal computer, Keithley 2400 I-V sourcemeter and Agilent 81110a pulse generator are adopted as the main hardware of the reliability measurement system whereas the data acquisition is accomplished via the LabVIEW programming language. The system operates based on the timeline concept instead of using the switching box commonly seen in other multi-instruments measurements. The system established in this study can be divided into three subsystems including: (1) automatically double-sweeping I-V curve measurement system which commands Keithley 2400 sourcemeter into four individual voltage sweep steps. It may automatically read out the electrical properties including RHRS, RLRS, VSET and VRESET when LabVIEW collects the raw I-V-R data; (2) semi-automatic endurance measurement system which may precisely control the output signals from the pulse generator based on the timeline concept and subsequently provide the resistivity-cycle profiles and the I-V curves; (3) automatic long-time retention measurement system which sets the starting point of timeline by Agilent 81110a and controls the interval time between two resistivity-read command of Keithley 2400 so as to record the long-time retention property of RRAM devices. The advantages of the whole system include cross-brand instrument integration, high degree of freedom of measurement, convenience of data analysis and low assembly cost. However, the endurance system can only be semi-automatic since the abandon of switch box inevitably requires the manual circuit exchange during I-V measurement.